Cloud Firestore is:

An industry-leading local SDD that integrates with the other products in the Google Cloud Platform suite.
An enterprise-grade database service built for the cloud speciﬁcally to combine the beneﬁts of relational database structure with relational horizontal scale.
A ﬂexible, scalable NoSQL cloud database to store and sync data for client- and server-side development.
A tool for developing and executing a wide range of data processing patterns on very large datasets.